What allowed native americans in mexico to settle cities larger than those in areas to the north?

The correct answer is the development of cities that were built by an earlier civilization.

Unlike North American cities, Mexican cities were older, bigger, and more adapted for native americans than northern cities.

The main reason why Native Americans in Mexico settled cities that were larger than those in areas to the North was the fact that there was an observable development of cities that were built by an earlier civilization.

This enabled for faster progress than  had been experienced before. 

Probably bc romania was invaded